Before bevel gear cutting, the residual stress in the material is evenly distributed and balanced along the thickness direction of bevel gear blank. During the processing of bevel gear blank, the material of bevel gear blank is gradually removed, the original equilibrium stress state is broken, and the residual stress will be redistributed until a new equilibrium is reached. After the bevel gear blank is cut, the bevel gear blank will be deformed in the process from the redistribution of residual stress to the new equilibrium state.
In another way, the deformation of bevel gear split wheel blank machining is the process of workpiece deformation caused by the disappearance of the internal stress contained in that part of the material due to the removal of the cogging material during gear cutting. Therefore, the reverse stress (the magnitude of the stress remains unchanged and the direction is opposite) can be applied on the left and right sides of the cogging to equivalent the influence of gear cutting on the deformation of bevel gear blank. However, the internal stress distribution of bevel gear blank in different material removal States is also different, and the corresponding reverse additional stress also changes.
It can be seen from the figure that the maximum deformation of bevel gear blank during gear cutting is near the machining area, and the deformation of the unprocessed area of bevel gear blank is small, and the farther away from the position of gear cutting, the smaller the influence of deformation on bevel gear blank. When the bevel gear is split and the first two tooth grooves at the left end are cut off, there is obvious bending deformation at and near the position of the first two tooth grooves of the bevel gear blank; When the first four grooves of the bevel gear blank are processed, the newly processed area of the bevel gear blank is further deformed obviously, but the deformation of the first two groove areas of the bevel gear blank is relatively small, and the unprocessed part of the bevel gear blank remains in a straight state; When the bevel gear split wheel blank is processed, the whole bevel gear blank is in the state of bending deformation.
From the above analysis, it can be inferred that the gear cutting of bevel gear split blank mainly deforms the machining area and has little influence on other positions of bevel gear blank. However, from the deformation value of bevel gear blank in the figure, it can also be seen that the deformation of bevel gear split blank in the processing process is the effect of continuous superposition on the basis of previous deformation. That is to say, after the bevel gear is split and the first two grooves are processed, the stress distribution inside the bevel gear blank has changed. When the bevel gear blank continues to cut teeth, its internal stress will produce new changes on the basis of the previous. When the cutting order of the bevel gear blank is different, its internal stress distribution state will also be different.
According to the above analysis, the residual stress redistribution of bevel gear split wheel blank is based on the previous stress state of bevel gear blank, and the superposition effect of previous deformation should also be considered for the deformation of bevel gear blank. When the deformation of bevel gear splitting wheel blank involves superposition effect and bidirectional stress, it is difficult to solve the calculation directly by analytical method, and it can be seen from the finite element analysis results that the stress in X direction changes the most in the process of wheel blank machining. Therefore, taking the removal of a single tooth groove in the middle of the bevel gear blank as an example, this paper analyzes the generation and calculation method of the additional torque in the X direction in the process of gear cutting, as well as the deformation of the bevel gear blank. The analysis and calculation of the overall deformation of the whole subdivision body will be obtained through the accumulation of deformation of multiple analysis elements.